PROJECT SUMMARY: Periodontal disease (PD), a common infectious/inflammatory disease, is preventable for much of the population by early detection and treatment; however, the high prevalence of PD (47% of Americans adults having periodontitis) makes it a public health concern, having a socio-economic burden of up to $442 billion each year. PD is typically diagnosed by the dental hygienist, dentist, or periodontist tracking alveolar bone height and gingival height through intraoral radiographs (X-rays) and periodontal probing. Dental X-rays are the most reliable intraoral imaging tool for identifying tooth/cavity conditions and bone lesions; however, dental X-rays cannot detect early periodontal lesions and visualize the topography of periodontal pocket (PP). Also, dental X-rays cannot be used as a routine screening tool to exam the progression of PD during the follow-up period because its ionizing radiation poses health risks and concerns. Periodontal probing is, therefore, the standard approach for complete PD diagnosis and follow-up checkups. The structural status of the periodontal soft tissues can be estimated by pocket depth measurement, gingival bleeding, and visual signs of gingival inflammation (redness and swelling). To the best of our knowledge, there is still no reliable technology that can provide 3D structure information of the PP and inflamed gingiva during PD progression. The objective of this proposal is to develop a smartphone-based infrared-fluorescence-imaging intraoral device (Smart-IR-ID) to measure the 3D structure of the PP and gingival inflammation for dentist-guided self-exam and tracking of PD. We propose to address this objective through 2 specific aims: 1) To investigate the infrared (IR) fluorescence imaging approach to develop IR intraoral devices that can precisely deliver and release the minimal required dosage of imaging agents into inflamed gingiva and PP; and 2) To develop the dual-module optical sensors and smartphone-based 3D modeling system for digital 3D IR-imaging and reporting the 3D measurements of PP and gingival inflammation. Our proposed project is innovative as a smartphone-based intraoral IR fluorescence imaging system in visualizing the 3D structure of PP and infected soft tissue of periodontium is a completely underexplored research area. The expected outcome of this work is to provide the pioneering prototype for our precision medicine-based intraoral imaging device integrated into a mHealth platform. Smart- IR-ID, in particular, opens the possibility of combining imaging and therapeutic capabilities at the next stage. Our project is significant because this research will develop a platform-specific model that can be linked to other intraoral diagnostic and therapeutic devices, transforming PD management from on-site clinical care in clinic facilities to dentist-guided self-care at the point-of-need.